Winter Plant Injury

The last ten years or so have seen normal to milder temperatures characterized by the absence of extreme cold like we have seen over the weekend to mid week, therefore there has been limited injury to ornamentals over this time period.

This year we are seeing temperatures that are running a few degrees below average and as noted an extremely cold snap that will last at least thru the day on Monday. In looking to spring what kind of damage can we expect from this colder than normal winter to date?

Typical winter damage can be seen as winter burn or physical damage from the weight of snow loads, damage that cant be seen is underground in the root zone. Damage rarely occurs on plants that are native to the area since they are well suited to the conditions. With ornamentals the damage will occur on plants that are at the northern edges of their hardiness zones.

Roots may be damaged or killed as a result of the extreme cold or they could be damaged by frost heave. Either way the best cure for root damage is to adequately insulate the soil with a thick layer of mulch. this will help to mitigate the extremes in temperature and limit any heaving in the soil.

To mitigate the effects of winter burn ensure plants have adequate moisture going into the winter months. If there is a time that the soil defrosts and you can water during the winter that will help as well. Applying an anti desiccant such as wilt proof prior to the temperatures staying in the low thirty's will also help to limit winter burn. Physical damage is generally caused by snow load on the branches of trees and shrubs. With colder temperatures the branches are brittle so be careful while removing the snow. Snow is actually a good insulator of the ground and plants during the cold months.

Some of the information included came from: The Effects of Cold January Temperatures on Landscape Plants. Ron Kujawski, Extension Educator UMass Extension Landscape, Nursery and Urban Forestry Program.